In recent years, electric vehicles, hybrid vehicles, fuel cell vehicles and the like have received attention as environmentally-friendly vehicles. These vehicles are each mounted with a motor that generates driving force for the vehicle to travel as well as a power storage device that stores electric power to be supplied to the motor. The hybrid vehicle is mounted with an internal combustion engine as a motive power source, in addition to the motor. The fuel cell vehicle is mounted with a fuel cell as a direct current (DC) power supply for driving the vehicle.
A vehicle is known in which a vehicle-mounted power storage device for driving the vehicle can be charged from a power supply for ordinary households. For example, a power supply outlet provided at a house is connected to a charging inlet provided at the vehicle by using a charging cable, so that electric power is supplied from the power supply for ordinary households to the power storage device. In the following, a vehicle in which a vehicle-mounted power storage device can be charged from a power supply provided externally to the vehicle will also be referred to as “plug-in vehicle”.
Japanese Patent Laying-Open No. 11-205909 (Patent Document 1) for example discloses a charging apparatus for charging a battery of an electric vehicle by means of an external power supply. According to this document, an electrical leakage breaker is provided between the electric vehicle and an outlet for the external AC power supply. The electrical leakage breaker is provided with a Hall sensor for detecting electrical leakage, a detection circuit and an electrical leakage relay. The electrical leakage breaker is further provided with an electrical leakage test relay for forcing a charging circuit to be short-circuited before charging, and an electrical leakage resistor. In a charging process, the electrical leakage test relay is closed to force short circuit to occur, and then it is confirmed whether or not the electrical leakage relay is broken. After it is confirmed that the breaker relay is broken, a charging relay is closed to start charging the battery.    Patent Document 1: Japanese Patent Laying-Open No. 11-205909